Unbaked laminate for producing front plate of plasma display device, and method for producing front plate of plasma display device

ABSTRACT

The present invention provides an unbaked laminate for producing a front plate ( 1 ) of a plasma display device, and a method for producing such a front plate ( 1 ). The laminate includes a burnable intermediate layer ( 14 ), and may include an unbaked dielectric layer ( 12 A) and a photosensitive unbaked spacer material layer ( 16 A). The burnable intermediate layer ( 14 ) positions between the dielectric layer ( 12 ) and the spacer material layer ( 16 ), and may burn up upon baking treatment, enabling removal of residues of the spacer material layer in the region subjected to its removal.

FIELD OF ART

The present invention relates to an unbaked laminate for producing afront plate of a plasma display device having a glass substrate withelectrodes formed on its surface, a dielectric layer formed on the glasssubstrate, and a patterned spacer layer on the dielectric layer. Thepresent invention also relates to a method for producing a front plateof a plasma display device.

BACKGROUND ART

A plasma display device (“PDP”), which displays an image by causing anumber of fine cells to emit light by themselves utilizing an electricdischarge phenomenon, has excellent features that cannot be realized byconventional display devices, such as a large and thin size, lightweight, and flat shape, which is becoming widespread.

Most of conventional plasma display devices employ cells having astraight structure in which ribs are formed only in the verticaldirection on the display surface. However, for efficiently introducinglight to the front of the plasma display device, there have recentlybeen developed cells having a waffle structure in which ribs are formednot only in the vertical direction but also in the horizontal direction.With the cells having such a waffle structure, leakage of light from theadjacent cells is prevented, enabling an extremely efficientintroduction of light to the front.

FIG. 1 is an exploded perspective view of an essential portion of aplasma display device having waffle cells. The plasma display deviceincludes a front plate 1 having combined electrodes 11 formed inparallel to one another wherein each combined electrode is made of atransparent electrode 110 and a bus electrode 112, and a back plate 2having address electrodes 21 formed in parallel to one another in thecross direction with respect to the combined electrodes 11. The frontplate 1 and the back plate 2 are disposed so as to face each other andunified to constitute a display element. The front plate 1 has atransparent glass substrate 10 as a display plane, and the combinedelectrodes 11 are disposed on the inner side of the glass substrate 10,namely, on the side thereof facing the back plate 2. A dielectric layer12 is formed so as to cover the combined electrodes 11, and a patternedspacer layer 16 is provided on the dielectric layer 12. A protectivelayer 19 made of, for example, MgO is formed on the surface of thedielectric layer 12 and the spacer layer 16. On the other hand, the backplate 2 has a substrate 20, which is provided with the addresselectrodes 21 disposed on a side of the substrate 20 facing the frontplate 1. A dielectric layer 22 is formed so as to cover the addresselectrodes 21, and the light emitting portions are formed on thedielectric layer 22 as described below.

The light emitting portions consist of a number of cells each of whichis located in a space at which the combined electrode 11 crosses theaddress electrode 21. Each cell is confined by ribs 24 formed on thedielectric layer 22 along the vertical and horizontal directions of thedisplay (i.e., the direction indicated by arrows V and H, respectivelyshown in FIG. 1). A fluorescent layer 26 is provided so as to cover thesidewall of the rib 24 and the surface of the dielectric layer 22 in therib, that is, the inner wall and bottom of each cell. In the plasmadisplay device, a predetermined voltage from an alternating power sourceis applied to the combined electrodes of the front plate to form anelectric field between the electrodes, so that an electric dischargeoccurs in the cells. This discharge results in generation of anultraviolet light, which further causes light emission of thefluorescent layer 26.

FIG. 2 is a perspective view of the front plate 1 of the plasma displaydevice having waffle cells, as seen from the back plate side. FIG. 3 isa cross-sectional view of the plasma display device having waffle cells.As shown in FIG. 2, in the plasma display device having the wafflestructure, a number of spacer layers 16 are provided on the dielectriclayer 12 so that they are arranged in a form of equally spaced lines. Asshown in FIG. 3, in the front plate 1, the spacer layer 16 is in contactwith the rib 24. A gap X is thus formed at the upper portion of eachcell surrounded by the rib 24, and a rare gas can be introduced to eachcell through the gap X.

A process for producing such a front plate is roughly classified into aproduction process utilizing a screen printing method and a productionprocess utilizing a photolithography method.

In the production process utilizing a screen printing method, a glasspaste layer is formed on the glass substrate 10 and baked at 500 to 700°C. to form the dielectric layer 12. On the dielectric layer 12, a glasspaste composition is then stacked in a patterned form by screenprinting, and further baked at 500 to 700° C. to form the spacer layer16.

However, the production process utilizing the screen printing method hasproblems of the cost for production due to the essential two bakingsteps, as well as a poor precision of the pattern alignment.

Referring to FIG. 10, the production process utilizing aphotolithography method is then described. On the glass substrate 10 areformed an unbaked dielectric layer 12A consisting of anon-photosensitive glass paste layer, as well as a photosensitive,unexposed unbaked spacer material layer 16A consisting of aphotosensitive glass paste layer. The spacer material layer 16A is thenirradiated with, e.g., an ultraviolet light through a photomask 3 (FIG.10A). The layer is then developed so that a resist pattern 16A′ appears(FIG. 10B). The resultant product is baked at 500 to 700° C. to form thedielectric layer 12 and the spacer layer 16 simultaneously (FIG. 10C).

In the production process utilizing a photolithography method, thedielectric layer 12 and the spacer layer 16 can be baked at the sametime in a single baking operation, and therefore the cost for productioncan be advantageously lowered, as compared to the cost for theproduction process utilizing a screen printing method.

However, upon appearance of the resist pattern after the developmenttreatment in such a production process, the spacer material oftenremains in regions other than the regions in which the material shouldbe left as a spacer layer (see FIG. 10B). Although the spacer materialresidue A remaining in the region that has been subjected to theremoving development (concave region) becomes somehow flat due tomelting of the glass frit component in the baking treatment, it causesunevenness of the exposed surface of the dielectric layer 12, leading toa problem that the thickness of the dielectric layer 12 between thespacer layers 16 becomes ununiform (see FIG. 10C).

As shown in FIG. 3, in the plasma display device, the light emittingportions are disposed between the spacer layers 16. When the thicknessof the dielectric layer 12 at that portion is not uniform, the lighttransmittance or electric discharge properties become ununiform, whichcan be one of the reason for causing distortion in the image.

DISCLOSURE OF THE INVENTION

The present invention has been made in view of the above-mentionedproblems accompanying the prior art. An object of the present inventionis therefore to provide a material with which a front plate of a plasmadisplay device having uniform discharge properties and lighttransmittance can be produced, and a method for producing the same.

The present inventors have conducted extensive studies with a viewtoward solving the problems described above. As a result, they haveobtained the following findings.

That is, the removal of the aforementioned spacer material residue maybe achieved by intercalating an intermediate layer between an unbakeddielectric layer and a spacer material layer formed thereon before thebaking treatment, wherein the intermediate layer is made of a materialwhich is soluble in or swellable with water or an aqueous solution fordevelopment and is burnable by a baking treatment, and then performingthe conventional exposure treatment and subsequent treatments. Since theintermediate layer burns up in the baking treatment, a laminatestructure which is the same as the conventional laminate structure canbe obtained after the baking treatment.

In addition, it has also been found out that layers having a uniformthickness and an excellent surface flatness can be produced bypreliminary forming the upper and the lower two or three layersincluding the intermediate layer on a removable support film, andtransferring the resultant laminate on a substrate.

The present invention has been achieved based on the finding describedabove. In summary, the unbaked laminate for producing a front plate of aplasma display device of the present invention is characterized in thaton a removable support film is formed any one of the followingcombinations (i) to (iii):

(i) a burnable intermediate layer and an unbaked dielectric layer;

(ii) a spacer material layer and a burnable intermediate layer; and

(iii) a spacer material layer, a burnable intermediate layer, and anunbaked dielectric layer.

That is, according to the present invention, there is provided anunbaked laminate for producing a front plate of a plasma display devicehaving a glass substrate having a surface on which electrodes areformed, a dielectric layer formed on the surface, and spacer layersformed on the dielectric layer, the laminate including: a removablesupport film; a burnable intermediate layer formed on the removablesupport film, the intermediate layer being water-soluble orwater-swellable; and an unbaked dielectric layer formed on the burnableintermediate layer, the dielectric layer consisting of a glass pastematerial.

According to the present invention, there is also provided an unbakedlaminate for producing a front plate of a plasma display device having aglass substrate having a surface on which electrodes are formed, adielectric layer formed on the surface, and spacer layers formed on thedielectric layer, the laminate including: a removable support film; aphotosensitive unbaked spacer material layer formed on the removablesupport film; and a burnable intermediate layer formed on the spacermaterial layer, the intermediate layer being water-soluble orwater-swellable.

According to the present invention, there is further provided an unbakedlaminate for producing a front plate of a plasma display device having aglass substrate having a surface on which electrodes are formed, adielectric layer formed on the surface, and spacer layers formed on thedielectric layer, the laminate including: a removable support film; aphotosensitive unbaked spacer material layer formed on the removablesupport film; a burnable intermediate layer formed on the spacermaterial layer, the intermediate layer being water-soluble orwater-swellable; and an unbaked dielectric layer formed on the burnableintermediate layer, the dielectric layer consisting of a glass pastematerial.

According to the present invention, there is further provided a methodfor producing a front plate of a plasma display device having a glasssubstrate having a surface on which electrodes are formed, a dielectriclayer formed on the surface, and spacer layers formed on the dielectriclayer, the method including the steps of: (a) forming on the surface ofthe substrate an unbaked dielectric layer consisting of a glass pastematerial, a burnable intermediate layer which is water-soluble orwater-swellable, and a photosensitive unbaked spacer material layer inthis order; (b) irradiating the spacer material layer with a patterninglight, and developing the spacer material layer, to constitute apatterned spacer material layer; (c) baking the unbaked dielectriclayer, the burnable intermediate layer, and the patterned spacermaterial layer simultaneously, to burn up the burnable intermediatelayer and forming the dielectric layer and the spacer layer on the glasssubstrate simultaneously.

As used herein, “unbaked laminate for producing a front plate of aplasma display device” refers to a laminate used in the production of afront plate of a plasma display device, having a removable support filmand the aforementioned layers formed thereon which are to be transferredand attached to a glass substrate while peeling the removable supportfilm off the layers.

As used herein, the “unbaked” laminate or layer refers to a laminate orlayer which is capable of being transformed by baking treatment to be alaminate or layer used in the plasma display device. For example, theunbaked dielectric layer is capable of being transformed by bakingtreatment to be a dielectric layer of the plasma display device; and theunbaked spacer material layer is capable of being transformed by bakingtreatment to be a spacer layer of the plasma display device.

In the production of the front plate of the plasma display device withthe unbaked laminate of the present invention, the water-soluble orwater-swellable, burnable intermediate layer is positioned between theunbaked dielectric layer and the spacer material layer. When the spacermaterial layer is irradiated with a patterning light and developing thespacer material layer to constitute a patterned spacer material layer, aresidue of the spacer material remains on the exposed surface of theburnable intermediate layer between the projecting portions of thepattern. However, with use of the unbaked laminate of the presentinvention, a residue of the spacer material is formed on the surface ofthe burnable intermediate layer, hence the spacer material residue maybe removed by a developer (water or aqueous solution), so that thespacer layer material can be readily prevented from remaining in theregion that has been subjected to the removing development.

In the unbaked laminate for producing a front plate of a plasma displaydevice of the present invention, it is preferred that the surface on theother side of the removable support film is protected by a removableprotective film.

It is preferred that the spacer material layer is a water-developable(i.e., capable of being developed by use of water) photosensitive glasspaste layer. It is preferred that the burnable intermediate layercontains at least one resin selected from the group consisting ofpolyvinyl alcohol, a polyvinyl alcohol derivative, and water-solublecellulose, and has a thickness of 5 micrometers or less.

The method for producing a front plate of a plasma display device of thepresent invention includes: laminating, on the surface of a glasssubstrate on which electrodes are formed, an unbaked dielectric layermade of a glass paste material, a burnable intermediate layer which iswater-soluble or water-swellable, and an unexposed, photosensitiveunbaked spacer material layer in this order from the lowest; irradiatingthe spacer material layer with a patterning light, and developing thespacer material layer to constitute a patterned spacer material layer;and baking the unbaked dielectric layer, the burnable intermediatelayer, and the patterned spacer material layer on the glass substratesimultaneously to permit the burnable intermediate layer to burn up,forming the dielectric layer and the spacer layer on the glass substratesimultaneously.

In the method for producing a front plate of a plasma display device ofthe present invention, it is preferred to use the unbaked laminate ofthe present invention for forming the burnable intermediate layer,unbaked dielectric layer, and/or spacer material layer on the glasssubstrate. That is, lamination of the burnable intermediate layer,unbaked dielectric layer, and/or spacer material layer on the glasssubstrate may preferably be performed by forming these layers on aremovable support film, followed by transfer of these layers to theglass substrate while peeling the removable support film off the layers.

In the method for producing a front plate of a plasma display device ofthe present invention, the use of the unbaked laminate of the presentinvention for placing the layers on the glass substrate may result inuniform thickness and excellent surface flatness of the layers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view showing a plasma display devicehaving waffle cells.

FIG. 2 is a perspective view showing a front plate of the plasma displaydevice as seen from the back plate side.

FIG. 3 is a cross-sectional view showing the plasma display devicehaving waffle cells.

FIGS. 4A to 4C are cross-sectional views showing typical embodiments ofthe unbaked laminates for producing a front plate of a plasma displaydevice of the present invention. In FIG. 4 et seq., numeral 18 denotes aremovable film, collectively refers to a support film and a protectivefilm.

FIGS. 5A to 5D are cross-sectional views showing a process for producinga front plate of a plasma display device using the unbaked laminate forproducing a front plate of a plasma display device of FIG. 4A.

FIG. 6 is a schematic view showing a step of transferring an unbakeddielectric layer 12A and burnable intermediate layer 14 to a glasssubstrate 10 using the unbaked laminate for producing a front plate of aplasma display device of FIG. 4A.

FIGS. 7A to 7D are cross-sectional views showing a process for producinga front plate of a plasma display device using the unbaked laminate forproducing a front plate of a plasma display device of FIG. 4B.

FIGS. 8A to 8C are cross-sectional views showing a process for producinga front plate of a plasma display device using the unbaked laminate forproducing a front plate of a plasma display device of FIG. 4C.

FIGS. 9A to 9D are cross-sectional views showing the exposure,development and baking steps in the method for producing a front plateof a plasma display device of the present invention.

FIGS. 10A to 10C are cross-sectional views showing a conventionalprocess for producing a front plate of a plasma display device.

BEST MODE FOR CARRYING OUT THE INVENTION

Typical embodiments of the unbaked laminate of the present invention mayinclude a bilayer structure having a burnable intermediate layer and anyone of an unexposed, photosensitive unbaked spacer material layer and anunbaked dielectric layer; as well as a trilayer laminate structurehaving an unbaked dielectric layer, a burnable intermediate layer, andan unexposed, photosensitive unbaked spacer material layer. It ispreferable that the laminate having the bilayer or trilayer structurehas readily removable films for covering both surfaces of the laminate,to facilitate storage, transportation, and handling.

Since the unbaked laminate of the present invention can be preliminarilyproduced and stored for a period of time, it can be immediately usedupon producing a front plate of a plasma display device, making itpossible to improve the efficiency of production of the front plate of aplasma display device. The essential and most important feature of theunbaked laminate resides in that the laminate has a burnableintermediate layer. The burnable intermediate layer is water-soluble orwater-swellable, and further has properties such that it burns upcompletely in a baking treatment.

In the production of a front plate of a plasma display device, theburnable intermediate layer is located between the unbaked dielectriclayer and the spacer material layer as will be described in detail belowin connection with the production method. When the spacer material layerin such a laminate is irradiated with a patterning light and developedto constitute a patterned spacer material layer, a residue of the spacermaterial remains on the exposed surface of the burnable intermediatelayer between the projecting portions of the pattern as described abovein connection with the conventional technology. In a conventionalproduction method, the spacer material residue remains as such, andmelts in a burning treatment to cause unevenness of the exposed surfaceof the dielectric layer, which should be a uniform and flat surface. Bycontrast, when using the unbaked laminate of the present invention, aresidue of the spacer material is formed on the surface of the burnableintermediate layer. If the burnable intermediate layer is water-soluble,the spacer material residue is washed away by a developer (water oraqueous solution), together with the burnable intermediate layer in theexposed region. If the burnable intermediate layer is water-swellable,it is swollen with a developer to allow the spacer material residuepresent on the surface of the burnable intermediate layer to leave thesurface, so that the residue can be easily removed by the developer.

The burnable intermediate layer, which has facilitated removal of thespacer material residue by a developer as mentioned above and hascompleted its role, burns up completely in a baking treatment for bakingthe unbaked dielectric layer and the unbaked spacer material layer.Consequently, a dielectric layer and a spacer layer having the sameconstruction and size as those of the conventional layers are formed ona glass substrate of a front plate. A difference between the resultantfront plate and the conventional front plate resides in that the exposedsurface of the dielectric layer between the spacer layer and theadjacent spacer layer is conventionally uneven, whereas, in the frontplate produced by the present invention, the exposed surface is flat.This is an extremely remarkable effect obtained by the unbaked laminateof the present invention having a water-soluble or water-swellable,burnable intermediate layer as a constituent.

The construction of each layer of the unbaked laminate of the presentinvention will be described hereinbelow, and then the method forproducing a front plate of a plasma display device using the unbakedlaminate of the present invention will be described in detail.

[A] Unbaked Laminate

FIG. 4 are cross-sectional views of typical embodiments of the unbakedlaminates of the present invention. FIG. 4A is an example of a bilayerlaminate structure including a burnable intermediate layer and anunbaked dielectric layer. In FIG. 4A, reference numeral 180 designates apeelable support film, and a burnable intermediate layer 14 is formed onthe support film. On the burnable intermediate layer 14, an unbakeddielectric layer 12A made of a glass paste material is formed, andcovered with a protective film 182 as a protective layer.

FIG. 4B is an example of a bilayer laminate structure comprising aspacer material layer and a burnable intermediate layer. In FIG. 4B, anunexposed, photosensitive unbaked spacer material layer 16A is formed onthe peelable support film 180. On the spacer material layer 16A, awater-soluble or water-swellable, burnable intermediate layer 14 isformed, and covered with the protective film 182 as a protective layer.

FIG. 4C is an example of a trilayer laminate structure comprising aspacer material layer, a burnable intermediate layer, and an unbakeddielectric layer. In FIG. 4C, the unexposed, photosensitive unbakedspacer material layer 16A is formed on the peelable support film 180. Onthe spacer material layer 16A, the water-soluble or water-swellable,burnable intermediate layer 14 is formed. On the burnable intermediatelayer 14, the unbaked dielectric layer 12A is formed. The surface of theunbaked dielectric layer 12A is protected by the protective film 182.

(a) Burnable Intermediate Layer

The burnable intermediate layer 14 is a layer which is water-soluble orwater-swellable. The burnable intermediate layer may be dissolved orswollen by washing with water to allow the unbaked spacer material layerremaining in the region that has been subjected to the removingdevelopment to leave the surface, thereby removing such a residue.

With respect to the burnable intermediate layer 14, there is noparticular limitation as long as it is water-soluble or water-swellableand decomposes or burns up by the baking treatment. The baking treatmentfor decomposing or burning up the intermediate layer may be carried outat 500 to 700° C. The intermediate layer may preferably include at leasteither one of a water-soluble resin and a water-swellable resin. It ispreferred that the burnable intermediate layer is formed using acomposition for forming the burnable intermediate layer, which includesat least either one of a water-soluble resin and a water-swellableresin, and a solvent.

(i) Water-soluble Resin or Water-swellable Resin

As the water-soluble resin, polyvinyl alcohol, a polyvinyl alcoholderivative, or water-soluble cellulose may preferably be used. As thewater-swellable resin, one obtained by partially crosslinking the abovewater-soluble resin may be used. These resins may be used individuallyor in combination.

Specific examples of the polyvinyl alcohol derivative may includesilanol-modified polyvinyl alcohol, cation-modified polyvinyl alcohol,mercapto group-containing polyvinyl alcohol, and butyral resins.

Specific examples of the water-soluble resin may include carboxymethylcellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxyethylmethyl, cellulose, hydroxypropyl cellulose, ethyl hydroxyethylcellulose, carboxymethyl ethyl cellulose, and hydroxypropyl methylcellulose.

Among these, polyvinyl alcohol and hydroxymethyl cellulose areparticularly preferred from the viewpoint of obtaining excellent watersolubility, heat decomposability, and solvent resistance (resistance ofthe dielectric layer against the solvent).

(ii) Solvent

The solvent for forming the burnable intermediate layer may preferablybe a solvent in which the water-soluble resin or water-swellable resinis readily soluble. The solvent may preferably be capable of giving aviscosity suitable for application to the composition, and being easilyremoved from the layer by drying evaporation. Examples of the solventmay include water, and an organic solvent, such as isopropyl alcohol.

(iii) Formation of Burnable Intermediate Layer

The burnable intermediate layer may be formed by diluting thewater-soluble resin or water-swellable resin with a solvent so as tohave a concentration suitable for application, applying the resultingcomposition to a surface for forming a layer, and then drying the layerfor removing the solvent.

The content of the water-soluble resin or water-swellable resin in theburnable intermediate layer composition for forming the burnableintermediate layer may preferably be 50% by weight or less, morepreferably 30% by weight or less, and the most preferably 0.1 to 20% byweight.

The thickness of the burnable intermediate layer may preferably be 20micrometers or less, more preferably 10 micrometers or less, furtherpreferably 5 micrometers or less. If the burnable intermediate layer istoo thick, the pattern in the unbaked spacer material layer isundesirably washed away in the subsequent step of washing with water.The most preferred thickness of the burnable intermediate layer is 0.1to 3 micrometers.

(b) Unbaked Dielectric Layer

The unbaked dielectric layer 12A consists of a glass paste layerobtained by applying a glass paste composition containing glass frit toa surface for forming a layer, and then drying the layer. When thedielectric layer 12A is subjected to the baking treatment, organicsubstances therein are removed and the glass frit therein is sintered,resulting in formation of a dielectric layer 12. The glass pastecomposition for forming the unbaked dielectric layer 12A may containglass frit, a bonding resin, and a solvent.

(i) Glass Frit

The glass frit to be contained in the glass paste composition maypreferably have desired transparency. Examples of the glass frit to beemployed may include glass powder of lead borosilicate glass, zincborosilicate glass, and bismuth borosilicate glass, such as PbO—SiO₂,PbO—B₂O₃—SiO₂, ZnO—SiO₂, ZnO—B₂O₃—SiO₂, BiO—SiO₂, and BiO—B₂O₃—SiO₂.

The particle size of the glass frit used may preferably have an averageparticle size of 0.1 to 10 micrometers, more preferably 0.5 to 8micrometers, depending on the shape of the pattern to be configured.When the average particle size of the glass frit is more than 10micrometers, the surface may be roughened upon forming a fine pattern,thus not being preferable. When the average particle size is less than0.1 micrometer, small pores may be formed during the baking to causeinsulation failure, thus not being preferable. Examples of forms of theglass frit may include a spherical form, a block form, a flake form, adendrite form, and combinations thereof.

In addition to the glass frit, the unbaked dielectric layer may furthercontain inorganic powders, such as ceramic (e.g., cordierite) or ametal. Specific examples of inorganic powders may include oxides of Na,K, Mg, Ca, Ba, Ti, Zr, and Al, such as cobalt oxide, iron oxide,chromium oxide, nickel oxide, copper oxide, manganese oxide, neodymiumoxide, vanadium oxide, cerium oxide tipaque yellow, cadmium oxide,ruthenium oxide, silica, magnesia, and spinel.

When the inorganic powders contain silicon oxide, aluminum oxide, ortitanium oxide, such an ingredient may cause the resulting layer to beopaque, which may result in low light transmittance. Therefore, it isdesired that the inorganic powders do not contain such an ingredient.

It is also preferred that an inorganic pigment capable of coloring thedielectric layer black, red, blue, or green is added as the inorganicpowder to form patterns each having a color so that the dielectric layerfunctions as a color filter of the plasma display device.

The inorganic powder may be a mixture of a plurality of sorts ofparticles each having different physical property values from others.Especially when using ceramic powders having a different heat softeningpoint from that of the glass frit, the shrinkage during the burning maybe suppressed. The inorganic powder may preferably be prepared byselecting the combination of the form and the physical property valuesdepending on the desired properties of the dielectric layer.

(ii) Bonding Resin

As the bonding resin contained in the glass paste composition, acrylicresins, cellulose derivatives, polyvinyl alcohol, polyvinyl butyral,polyethylene glycol, urethane resins, and melamine resins are known.Preferred are acrylic resins, especially acrylic resins having ahydroxyl group since they exhibit excellent heat adhesion properties toa glass substrate.

Examples of the acrylic resin having a hydroxyl group may includecopolymers obtained by polymerizing monomers having a hydroxyl group asa main copolymerizable monomer and, if necessary, other monomerscopolymerizable with them. As the monomer having a hydroxyl group,preferred are monoesters of acrylic acid or methacrylic acid and amonoalcohol having 1 to 20 carbon atoms. Examples of the monomer mayinclude hydroxymethyl acrylate, hydroxymethyl methacrylate,2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropylacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate,3-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutylmethacrylate, 3-hydroxybutyl acrylate, 3-hydroxybutyl methacrylate,4-hydroxybutyl acrylate, and 4-hydroxybutyl methacrylate. Examples ofthe monomers may also include monoesters of acrylic acid or methacrylicacid and a glycol having 1 to 10 carbon atoms, and epoxy ester compoundsmade from glycerol acrylate, glycerol methacrylate, dipentaerythritolmonoacrylate, dipentaerythritol monomethacrylate,ε-caprolactone-modified hydroxyethyl acrylate, ε-caprolactone-modifiedhydroxyethyl methacrylate, and 2-hydroxy-3-phenoxypropyl acrylate.

Examples of other monomers copolymerizable with the monomer having ahydroxyl group may include α,β-unsaturated carboxylic acids, such asacrylic acid, methacrylic acid, itaconic acid, citraconic acid, maleicacid, and fumaric acid, and anhydrides and half esters thereof;α,β-unsaturated carboxylic acid esters, such as methyl acrylate, ethylacrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate,isobutyl acrylate, sec-butyl acrylate, cyclohexyl acrylate, 2-ethylhexylacrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate,n-propyl methacrylate, isopropyl methacrylate, sec-propyl methacrylate,n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate,cyclohexyl methacrylate, 2-ethylhexyl methacrylate, stearylmethacrylate, 2,2,2-trifluoromethyl acrylate, and 2,2,2-trifluoromethylmethacrylate; and styrenes, such as styrene, α-methylstyrene, andp-vinyltoluene. In addition, acrylonitrile, methacrylonitrile,acrylamide, methacrylamide, vinyl acetate, glycidyl acryalte, andglycidyl methacryalte may be used. These monomers may be usedindividually or in combination.

(iii) Solvent

The solvent to be contained in the glass paste composition may be asolvent in which the organic component is well soluble. The solvent maysuitably selected so that the resulting photosensitive glass pastecomposition has an appropriate viscosity. It is preferable that thesolvent can be easily removed by drying evaporation. Especiallypreferred examples of solvents may include ketones, alcohols, and estershaving a boiling point of 100 to 200° C.

Specific examples of solvents may include ketones, such as diethylketone, methyl butyl ketone, dipropyl ketone, and cyclohexanone;alcohols, such as n-pentanol, 4-methyl-2-pentanol, cyclohexanol, anddiacetone alcohol; ether alcohols, such as ethylene glycol monomethylether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether,propylene glycol monomethyl ether, propylene glycol monoethyl ether,diethylene glycol monomethyl ether, diethylene glycol monoethyl ether,diethylene glycol dimethyl ether, and diethylene glycol diethyl ether;saturated aliphatic monocarboxylic acid alkyl esters, such as n-butylacetate and amyl acetate; lactic acid esters, such as ethyl lactate andn-butyl lactate; and ether esters, such as methyl cellosolve acetate,ethyl cellosolve acetate, propylene glycol monomethyl ether acetate,propylene glycol monoethyl ether acetate, ethyl 3-ethoxypropionate,2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate,2-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate,3-ethyl-3-methoxybutyl acetate, 2-ethoxybutyl acetate, 4-ethoxybutylacetate, 4-propoxybutyl acetate, and 2-methoxypentyl acetate. Thesesolvents may be used individually or in combination.

(iv) Formation of Unbaked Dielectric Layer

The unbaked dielectric layer may be formed by forming a layer of theglass paste composition, and then drying the layer to remove thesolvent.

Preferable ratio of the amount of the inorganic component (the sum ofthe glass frit and the inorganic particles) and the amount of theorganic component (including a bonding resin) is as follows: relative to100 parts by weight of the sum of the inorganic component and theorganic component, the amount of the organic component may be in therange of 5 to 40 parts by weight and the amount of the inorganiccomponent may be in the range of 95 to 60 parts by weight; and it ispreferred that the amount of the organic component is in the range of 7to 35 parts by weight and the amount of the inorganic component is inthe range of 93 to 65 parts by weight; and it is further preferred thatthe amount of the organic component is in the range of 10 to 30 parts byweight and the amount of the inorganic component is in the range of 90to 70 parts by weight. When the amount of the organic component is lessthan 5 parts by weight, it may become difficult to form a layer; whereaswhen the amount of the organic component is more than 40 parts byweight, the shrinkage after the burning may disadvantageously become toolarge.

For maintaining the viscosity of the glass paste composition in anappropriate range, the amount of the solvent is preferably 300 parts byweight or less, more preferably 10 to 70 parts by weight, and mostpreferably 25 to 35 parts by weight, relative to 100 parts by weight ofthe sum of the inorganic component and the organic component.

In addition to the aforementioned components including the glass frit,bonding resin and solvent, the glass paste composition may furthercontain an arbitrary component as an additive, such as a plasticizer, adispersant, a tackifier, a surface tension adjuster, a stabilizer, or adefoamer.

The thickness of the unbaked dielectric layer after being dried ispreferably 10 to 100 micrometers, and more preferably 25 to 70micrometers.

(c) Spacer Material Layer

A spacer material layer 16A may consist of a layer of photosensitiveglass paste composition. Such a spacer material layer may be produced byforming a layer of the photosensitive glass paste composition on asurface, and drying the layer. As used herein, the spacer material layerrefers to a layer which is transformed to be a spacer layer by bakingtreatments. The spacer material layer 16A may be subjected tophotolithography for forming a pattern, and then subjected to bakingtreatment for removing organic substances and simultaneously sinteringglass frit, to form a spacer layer 16.

The photosensitive glass paste composition for forming the spacermaterial layer may be those having a sufficient transparency to anultraviolet light, an excimer laser, an X-ray, or an electron beam(these may be referred to hereinbelow as “light”) for conducting theexposure treatment. The photosensitive glass paste composition maypreferably be those with which a spacer material layer in which apattern with high precision can be formed by a photolithography method.

Examples of such a photosensitive glass paste composition may include,for example, photosensitive paste compositions disclosed in JapanesePatent Application Laid-open No. 2000-268633, Japanese PatentApplication Laid-open No. 2000-53444, Japanese Patent ApplicationLaid-open No. H11-246638, and Japanese Patent Application Laid-open No.2002-328470.

The photosensitive glass paste composition may preferably bewater-developable since the development step for forming the dielectricpattern and the step of washing with water can be conductedsimultaneously to simplify the production process. Such awater-developable composition generally has an excellent lighttransmittance and can maintain high light transmittance even when itcontains a large amount of the organic component, which enables patternformation with high precision in the photolithography.

The photosensitive glass paste composition may contain a resistcomposition, glass frit, and a solvent. As the glass frit and solvent,the same ones as those used in the glass paste composition describedabove in the section “(b) Unbaked dielectric layer” may be used.

The resist composition used in the photosensitive glass pastecomposition may contain a bonding resin, a photopolymerizable monomer,and a photopolymerization initiator.

(i) Bonding Resin

As the bonding resin in the photosensitive glass paste composition, thesame one as the bonding resin used in the glass paste compositiondescribed above in the section “(b) Unbaked dielectric layer” may beused. Particularly, the photosensitive glass paste composition maypreferably contain an acrylic resin having a hydroxyl group and awater-soluble cellulose derivative in combination since such acomposition has an improved transmittance of an active light, such asultraviolet light, an excimer laser, an X-ray, or an electron beam,enabling formation of a pattern with high precision.

As the water-soluble cellulose derivative, one conventionally known maybe used without any particular limitation. Examples thereof may includecarboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethylcellulose, hydroxyethyl methyl cellulose, hydroxypropyl cellulose, ethylhydroxyethyl cellulose, carboxymethyl ethyl cellulose, and hydroxypropylmethyl cellulose.

(ii) Photopolymerizable Monomer

As the photopolymerizable monomer, a conventionally knownphotopolymerizable monomer may be used without any particularlimitation. Examples thereof may include benzyl acrylate, benzylmethacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, phenoxyethylacrylate, phenoxyethyl methacrylate, phenoxypolyethylene glycolacrylate, phenoxypolyethylene glycol methacrylate, styrene,nonylphenoxypolyethylene glycol monoacrylate, nonylphenoxypolyethyleneglycol monomethacrylate, nonylphenoxypolypropylene glycol monoacrylate,nonylphenoxypolypropylene glycol monomethacrylate,2-hydroxy-3-phenoxypropyl acrylate, 2-acryloyloxyethyl phthalate,2-acryloyloxyethyl-2-hydroxyethyl phthalate,2-methacryloyloxyethyl-2-hydroxypropyl phthalate, methyl acrylate, ethylacrylate, methyl methacrylate, ethyl methacrylate, n-propyl acrylate,n-propyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethylmethacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate,3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, ethylene glycolmonoacrylate, ethylene glycol monomethacrylate, glycerol acrylate,glycerol methacrylate, dipentaerythritol monoacrylate, dipentaerythritolmonomethacrylate, dimethylaminoethyl acrylate, dimethylaminoethylmethacrylate, tetrahydrofurfuryl acrylate, tetrahydrofurfurylmethacrylate, phthalic acid-modified monoacrylate, ethylene glycoldiacrylate, ethylene glycol dimethacrylate, triethylene glycoldiacrylate, triethylene glycol dimethacrylate, trimethylolpropanetriacrylate, trimethylolpropane trimethacrylate, trimethylolethanetriacrylate, trimethylolethane trimethacrylate, pentaerythritoldiacrylate, pentaerythritol dimethacrylate, pentaerythritol triacrylate,pentaerythritol trimethacrylate, pentaerythritol tetraacrylate,pentaerythritol tetramethacrylate, dipentaerythritol tetraacrylate,dipentaerythritol tetramethacrylate, dipentaerythritol pentaacrylate,dipentaerythritol pentamethacrylate, dipentaerythritol hexaacrylate,dipentaerythritol hexamethacrylate, glycerol acrylate, glycerolmethacrylate, cardoepoxy diacrylate, and fumaric acid esterscorresponding to the above-mentioned compounds in which (meth)acrylateis replaced by fumarate, itaconic acid esters corresponding to theabove-mentioned compounds in which (meth)acrylate is replaced byitaconate, and maleic acid esters corresponding to the above-mentionedcompounds in which (meth)acrylate is replaced by maleate.

(iii) Photopolymerization Initiator

As the photopolymerization initiator, one generally known may be used.Examples thereof may include benzophenones, benzoins, benzoin alkylethers, acetophenones, aminoacetophenones, benzyls, benzyl alkyl ketals,anthraquinones, ketals, and thioxanthones. Specific examples thereof mayinclude 2,4-bis-trichloromethyl-6-(3-bromo-4-methoxy)phenyl-s-triazine,2,4-bis-trichloromethyl-6-(2-bromo-4-methoxy)phenyl-s-triazine,2,4-bis-trichloromethyl-6-(3-bromo-4-methoxy)styrylphenyl-s-triazine,2,4-bis-trichloromethyl-6-(2-bromo-4-methoxy)styrylphenyl-s-triazine,2,4,6-trimethylbenzoyidiphenylphosphine oxide,1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one,2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, 2-chlorothioxanthone,1-chloro-4-propoxythioxanthone, 3,3-dimethyl-4-methoxybenzophenone,benzophenone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one,1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one,4-benzoyl-4′-methyldimethyl sulfide, 4-dimethylaminobenzoic acid, methyl4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, butyl4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2-isoamyl4-dimethylaminobenzoate, 2,2-diethoxyacetophenone, benzyl dimethylketal, benzyl-β-methoxyethyl acetal, 1-phenyl-1,2-propanedione2-(o-ethoxycarbonyl)oxime, methyl o-benzoylbenzoate,bis(4-dimethylaminophenyl) ketone, 4,4′-bisdiethylaminobenzophenone,benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoinisopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether,p-dimethylaminoacetophenone, p-tert-butyltrichloroacetophenone,p-tert-butyldichloroacetophenone, thioxanthone, 2-methylthioxanthone,2-isopropylthioxanthone, dibenzosuberone,α,α-dichloro-4-phenoxyacetophenone, pentyl 4-dimethylaminobenzoate, and2-(o-chlorophenyl)-4,5-diphenylimidazolyl dimer. These initiators may beused individually or in combination.

(iv) Formation of Spacer Material Layer

The spacer material layer may be formed by forming a layer of thephotosensitive glass paste composition on a surface, and then drying thelayer to remove the solvent therein.

Relative to 100 parts by weight of the sum of the water-solublecellulose derivative and the acrylic resin having a hydroxyl group inthe photosensitive glass paste composition, the amount of thewater-soluble cellulose derivative may be in the range of 50 to 90 partsby weight and the amount of the acrylic resin having a hydroxyl groupmay be in the range of 50 to 10 parts by weight; and it is preferredthat the amount of the water-soluble cellulose derivative is in therange of 60 to 80 parts by weight and the amount of the acrylic resinhaving a hydroxyl group is 40 to 20 parts by weight; and it is furtherpreferred that the amount of the water-soluble cellulose derivative isin the range of 60 to 70 parts by weight and the amount of the acrylicresin having a hydroxyl group is 40 to 30 parts by weight.

Relative to 100 parts by weight of the sum of the amount of thewater-soluble cellulose derivative and the amount of thephotopolymerizable monomer, the amount of the water-soluble cellulosederivative may be in the range of 10 to 50 parts by weight and theamount of the photopolymerizable monomer may be in the range of 90 to 50parts by weight; and it is preferred that the amount of thewater-soluble cellulose derivative is in the range of 20 to 40 parts byweight and the amount of the photopolymerizable monomer is in the rangeof 80 to 60 parts by weight; and it is further preferred that the amountof the water-soluble cellulose derivative is in the range of 25 to 35parts by weight and the amount of the photopolymerizable monomer is inthe range of 75 to 65 parts by weight.

The amount of the photopolymerization initiator may preferably be usedin the range of 0.1 to 10 parts by weight, more preferably in the rangeof 0.2 to 5 parts by weight, per 100 parts by weight of the sum of thewater-soluble cellulose derivative and the photopolymerizable monomer.When the amount of the photopolymerization initiator is less than 0.1part by weight, the curing properties of the composition may becomepoor. When the amount of the photopolymerization initiator is more than10 parts by weight, failure of curing may occur in the bottom due toabsorption of the initiator.

Preferable ratio of the amount of the organic component (including abonding resin such as a water-soluble cellulose derivative or an acrylicresin, and a photopolymerization initiator), and the amount of theinorganic component (the sum of the glass frit and the inorganicparticles) is as follows: relative to 100 parts by weight of thephotosensitive glass paste composition, the amount of the organiccomponent may be in the range of 10 to 40 parts by weight and the amountof the inorganic component may be in the range of 90 to 60 parts byweight; and it is preferred that the amount of the organic component isin the range of 15 to 35 parts by weight and the amount of the inorganiccomponent is in the range of 85 to 65 parts by weight; and it is furtherpreferred that the amount of the organic component is in the range of 20to 30 parts by weight and the amount of the inorganic component is inthe range of 80 to 70 parts by weight.

The amount of the solvent may preferably be 300 parts by weight or less,more preferably 10 to 70 parts by weight, the most preferably 25 to 35parts by weight, per 100 parts by weight of the sum of the inorganiccomponent and the organic component, for maintaining the viscosity ofthe photosensitive glass paste composition in a preferred range.

In addition to the above ingredients, the photosensitive glass pastecomposition may further contain an additive component, such as anultraviolet light absorber, a sensitizer, a sensitizing auxiliary, apolymerization inhibitor, a plasticizer, a thickener, an organicsolvent, a dispersant, a deformer, or an organic or inorganicanti-precipitation agent.

The thickness of the unexposed, photosensitive unbaked spacer materiallayer obtained by drying a layer of the photosensitive glass pastecomposition may be in a range of 10 to 50 micrometers, preferably 15 to40 micrometers.

(d) Method for Producing an Unbaked Laminate

A support film 180 used in the unbaked laminate of the present inventionmay be a removable film such that the layers formed on the support filmcan be easily peeled off therefrom and transferred to a glass substrate.Examples thereof may include flexible films having a thickness of 15 to125 micrometers consisting of a synthetic resin film, such aspolyethylene terephthalate, polyethylene, polypropylene, polycarbonate,or polyvinyl chloride. It is preferred that the support film is treatedso as to be removable if necessary for facilitating transfer.

In the formation of the spacer material layer 16A, the burnableintermediate layer 14, and the unbaked dielectric layer 12A on thesupport film, compositions for forming each of the layers are prepared,and applied to the support film 180 using an applicator, a bar coater, awired bar coater, a roll coater, or a curtain flow coater. The rollcoater is especially preferred since it achieves excellent uniformity inthe application thickness and can efficiently form a layer having asatisfactorily large thickness. The layer of the composition applied maybe dried and another composition for forming another layer may then beapplied to the dried layer. In such a manner, each layer may belaminated, for producing the unbaked laminate of the present inventionshown in FIGS. 4A to 4C.

It is preferred that the surface of the unbaked laminate on the otherside of the support film 180 is covered with a protective film 182 forstably protecting, for example, the photosensitive paste compositionlayer before use. The protective film may preferably be a polyethyleneterephthalate film, a polypropylene film, or a polyethylene film, havingsilicone coated or baked thereon and having a thickness of about 15 to125 micrometers.

[B] Method for Producing a Front Plate of a Plasma Display Device

The method for producing a front plate of a plasma display device of thepresent invention may include: laminating, on the surface of a glasssubstrate on which electrodes are formed, an unbaked dielectric layermade of a glass paste material, a burnable intermediate layer which iswater-soluble or water-swellable, and an unexposed, photosensitiveunbaked spacer material layer in this order from the lowest; irradiatingthe spacer material layer with a patterning light, and developing thespacer material layer to constitute a patterned spacer material layer;and baking the unbaked dielectric layer, the burnable intermediatelayer, and the patterned spacer material layer on the glass substratesimultaneously to permit the burnable intermediate layer to burn up,forming the dielectric layer and the spacer layer on the glass substratesimultaneously.

(a) Formation of Layers on Glass Substrate

Stacking of the burnable intermediate layer, the unbaked dielectriclayer, and the spacer material layer on the glass substrate may beperformed by any of the conventionally known method, such as anapplication method or a screen printing method, without any limitation.From the viewpoint of forming layers having uniform thickness andexcellent surface flatness, the method for forming the layers using theunbaked laminate of the present invention shown in FIGS. 4A to 4Cdescribed above is the most preferred.

Referring to FIGS. 5A to 5D and FIG. 6, an example of the process forproducing a front plate of a plasma display device using the unbakedlaminate shown in FIG. 4A is described. First, the support film 180,burnable intermediate layer 14, unbaked dielectric layer 12A, andprotective film 182 are stacked on one another in this order to preparean unbaked laminate (FIG. 5A). Subsequently, as shown in FIG. 6, whilepeeling the protective film 182 off, the unbaked laminate is placed onthe glass substrate 10 so that the unbaked dielectric layer 12A thusuncovered is in contact with the surface of the glass substrate 10 onwhich the electrodes 11 are formed, and a heat roller 40 is moved overthe support film 180 to hot-press the unbaked dielectric layer 12A andburnable intermediate layer 14 against the surface of the glasssubstrate (FIG. 5B).

The hot press may preferably be conducted under conditions such that theglass substrate 10 is heated so that the surface temperature becomes 80to 140° C., the roll pressure is in the range of 1 to 5 kg/cm², and themoving speed is in the range of 0.1 to 10.0 m/min. The glass substratemay be preheated, and the preheat temperature may be selected in therange of, for example, 40 to 100° C.

The protective film 182 that has been peeled off from the unbakeddielectric layer 12A may successively be taken up by a take-up roller 42and stored in the form of a roll, which can be reused.

After providing the unbaked dielectric layer 12A and burnableintermediate layer 14 on the surface of the glass substrate 10 byheat-bonding in such a manner (FIG. 5B), the support film 180 is thenpeeled off from the burnable intermediate layer 14 to uncover thesurface of the burnable intermediate layer 14 (FIG. 5C). The supportfilm 180 peeled off from the burnable intermediate layer 14 may also betaken up successively by a take-up roller and stored in the form of aroll, which can be reused.

The spacer material layer 16A is then stacked on the uncovered surfaceof the burnable intermediate layer 14 (FIG. 5D). Although there is nolimitation to the method for stacking the spacer material layer 16A, itis preferred that the spacer material layer is stacked by the samemethod as the method for forming the burnable intermediate layer or theunbaked dielectric layer. Specifically, it is preferred that thephotosensitive glass paste composition is applied to a support film anddried to form the spacer material layer 16A, and the resultant productis stacked on the burnable intermediate layer 14 so that the spacermaterial layer 16A is in contact with the burnable intermediate layer14, and a heat roller is moved over the support film to transfer thespacer material layer 16A to the surface of the burnable intermediatelayer 14.

Referring to FIGS. 7A to 7D, an example of the process for producing afront plate of a plasma display device using the unbaked laminate shownin FIG. 4B is then described. First, the support film 180, the spacermaterial layer 16A, the burnable intermediate layer 14, and theprotective film 182 are stacked on one another in this order to preparean unbaked laminate (FIG. 7A). Separately, the unbaked dielectric layer12A is formed on the surface of the glass substrate 10 on which theelectrodes 11 are formed (FIG. 7B). Although there is no limitation tothe method for forming the unbaked dielectric layer 12A, it is preferredthat the glass paste composition is applied to a support film and driedto form the unbaked dielectric layer 12A, and the resultant product isstacked on the glass substrate 10 so that the unbaked dielectric layer12A is in contact with the surface of the glass substrate 10 on whichthe electrodes 11 are formed, and a heat roller is moved over thesupport film to transfer the unbaked dielectric layer 12A to the glasssubstrate 10. The protective film 182 in the unbaked laminate of FIG. 7Ais peeled off and the unbaked-laminate burnable intermediate layer 14 isbrought into contact with the surface of the unbaked dielectric layer12A, and the heat roller 40 is moved over the support film 180 toheat-bond the burnable intermediate layer 14 and spacer material layer16A to the unbaked dielectric layer 12A (FIG. 7C). The support film 180is then peeled off from the spacer material layer 16A, to form theunbaked dielectric layer 12A, burnable intermediate layer 14, and spacermaterial layer 16A on the glass substrate 10 (FIG. 7D).

Referring to FIGS. 8A to 8C, an example of the process for producing afront plate of a plasma display device using the unbaked laminate shownin FIG. 4C is then described. First, the support film 180, the spacermaterial layer 16A, the burnable intermediate layer 14, the unbakeddielectric layer 12A, and the protective film 182 are stacked on oneanother in this order to prepare an unbaked laminate (FIG. 8A). Theprotective film 182 in the unbaked laminate is peeled off to uncover theunbaked dielectric layer 12A, and the unbaked dielectric layer 12A isbrought into contact with the surface of the glass substrate 10 on whichthe electrodes 11 are formed, and the heat roller 40 is moved oversupport film 180 to heat-bond the layers to the surface of the glasssubstrate (FIG. 8B). The support film 180 is then peeled off from thespacer material layer 16A, to form the unbaked dielectric layer 12A,burnable intermediate layer 14, and spacer material layer 16A on theglass substrate 10 (FIG. 8C).

(b) Exposure and Development Treatment

Now referring to FIG. 9A to 9D, an example of the steps of the lightexposure and development treatment is described. After forming theunbaked dielectric layer 12A, the burnable intermediate layer 14, andthe spacer material layer 16A on a glass substrate in accordance withthe method described above, the photomask 3 is placed on the spacermaterial layer 16A, followed by exposure of the spacer material layer tolight, for curing a patterned region of the spacer material layer (FIG.9A).

When the spacer material layer 16A contains a photosensitive materialwhich hardly undergoes a curing reaction in the presence of oxygen, theexposure may preferably be performed with a transparent film coveringthe surface of the spacer material layer 16A. For example, when atransparent film is used as the support film 180 of the unbaked laminateof the present invention, the exposure step may preferably be performedafter stacking the layers on a glass substrate and before peeling offthe support film. That is, the exposure may be performed with thesupport film 180 covering the spacer material layer 16A, and the supportfilm 180 is then peeled off after completion of the exposure.

The apparatus for irradiation used in the exposure step may include anultraviolet light irradiation apparatus generally used in aphotolithography method, or an exposure system used in the fabricationof semiconductor or liquid crystal display device.

The uncured portion 16A of the spacer material layer is then removed bydevelopment, so that the resist pattern 16A′ appears (see FIG. 9B).

In the development treatment, a general-purpose alkaline developer orwater may be used. Examples of alkali components of the alkalinedeveloper may include hydroxides, carbonates, bicarbonates, phosphates,and pyrophosphates of an alkali metal, such as lithium, sodium, orpotassium; primary amines, such as benzylamine and butylamine; secondaryamines, such as dimethylamine, dibenzylamine, and diethanolamine;tertiary amines, such as trimethylamine, triethylamine, andtriethanolamine; cyclic amines, such as morpholine, piperazine, andpyridine; polyamines, such as ethylenediamine and hexamethylenediamine;ammonium hydroxides, such as tetramethylammonium hydroxide,tetraethylammonium hydroxide, trimethylbenzylammonium hydroxide, andtrimethylphenylbenzylammonium hydroxide; trimethylsulfonium hydroxides;sulfonium hydroxides, such as trimethylsulfonium hydroxide,diethylmethylsulfonium hydroxide, and dimethylbenzylsulfonium hydroxide;choline; and silicate-containing buffers. Among the above, water isparticularly preferred considering damage caused by the alkali componentof frit.

When constituting a patterned spacer material layer, a residue of thespacer material remains on the exposed surface of the burnableintermediate layer between the projecting regions of the pattern (see Ain FIG. 9B). In the method of the present invention, the residue A ofthe spacer material is formed on the surface of the burnableintermediate layer 14.

When the burnable intermediate layer 14 is water-soluble, the spacermaterial residue A is washed away by a developer (water or aqueoussolution), together with the burnable intermediate layer in the exposedregion as shown in FIG. 9C. When the burnable intermediate layer iswater-swellable, the burnable intermediate layer 14 is swollen with adeveloper as shown in FIG. 9C′, to allow the spacer material residue Apresent on the surface of the burnable intermediate layer to leave thesurface, so that the residue can be easily removed by the developer.

In the present invention, the spacer material residue A remaining in theregions in which the spacer material should be removed can be easilywashed away in the step of washing the surface with a developer (wateror an aqueous solution).

As used herein, the term “washing” means to bring it into contact with adeveloper (water or an aqueous solution). The method for washing maysuitably be selected from any method by which the burnable intermediatelayer 14 can be dissolved or swollen to remove the spacer materialresidue remaining in the region that has been subjected to the removingdevelopment. Specific examples of the method for washing may include adipping method, a rocking method, a shower method, a spraying method,and a paddle method.

(c) Baking

When the patterned laminate is baked at 500 to 700° C., the glass fritcontained in unbaked dielectric layer 12A and unbaked spacer materiallayer 16A′ is sintered to form the dielectric layer 12 and the spacerlayer 16, respectively, thus obtaining the front plate of a plasmadisplay device of the present invention having the patterned spacerlayer 16 on the dielectric layer 12 (see FIG. 9D). The organicsubstances contained in the laminate volatilize or decompose in thebaking step, and therefore the burnable intermediate layer 14 does notremain in the laminate after the baking. The front plate usually has aplurality of spacer layers which have a uniform thickness.

After manufacturing the front plate of a plasma display device having aglass substrate with electrodes formed on its surface, a dielectriclayer formed on the glass substrate, and a patterned spacer layer on thedielectric layer as described above, the uncovered surface of thedielectric layer and the spacer layer may preferably be covered with aprotective layer 19 made of, for example, MgO.

As mentioned above, with the method for producing a front plate of aplasma display device of the present invention, the water-soluble and/orwater-swellable, burnable intermediate layer 14 is formed between theunbaked dielectric layer 12A and the unexposed, photosensitive unbakedspacer material layer 16A and, after forming a pattern, a residue of thespacer material layer remaining in the region that is subjected to theremoving development can be washed away by the developing liquid,resulting in an improved flatness of the region subjected to theremoving development, thus making it possible to produce a front plateof a plasma display device having uniform discharge properties and lighttransmittance.

EXAMPLES

The present invention will be described with reference to the followingExamples, but the Examples are merely working examples for illustratingthe present invention and should not be construed as limiting the scopeof the present invention. In the following descriptions, ComparativeExample is shown together with the Examples.

Example 1

(1) Preparation of Composition for Burnable Intermediate Layer

Four parts by weight of polyvinyl alcohol (Trade name: PVA-235, byKuraray Co., Ltd.), and 53 parts by weight of water and 43 parts byweight of isopropyl alcohol as a solvent were mixed and stirred by astirrer for 12 hours to prepare a composition for forming awater-soluble burnable intermediate layer.

(2) Formation of Burnable Intermediate Layer

The obtained composition for forming the burnable intermediate layer wasapplied to a removable support film made of polyethylene terephthalate(Trade name: Purex A53, by Teijin DuPont Films Japan Limited) using alip coater, and the resultant layer was dried at 100° C. for 6 minutesto completely remove the solvent, thus forming a burnable intermediatelayer having a thickness of 0.5 micrometer on the support film.

(3) Preparation of Glass Paste Composition

20 Parts by weight of an isobutyl methacrylate/hydroxyethylacrylate=80/20 (wt %) copolymer (Mw: 20,000) as an acrylic resin, 20parts by weight of 3-methoxy-3-methylbutanol as a solvent, and 80 partsby weight of glass frit were mixed and kneaded to prepare a glass pastecomposition.

(4) Formation of Unbaked Dielectric Layer

The glass paste composition obtained was applied using a lip coater tothe burnable intermediate layer on the support film obtained in (2)above, and the resultant layer was dried at 100° C. for 60 minutes tocompletely remove the solvent, thus forming an unbaked dielectric layerhaving a thickness of 60 micrometers on the support film. Removablepolyethylene terephthalate film (Trade name: Purex A53, by Teijin DuPontFilms Japan Limited) having a thickness of 25 micrometers was thenstacked on the unbaked dielectric layer to produce an unbaked laminatefor transferring the unbaked dielectric layer and the burnableintermediate layer.

(5) Preparation of Water-Developable Resist Composition

22 Parts by weight of hydroxypropyl cellulose as a water-solublecellulose derivative, 14 parts by weight of a styrene/hydroxyethylmethacrylate=55/45 (wt %) copolymer (Mw: 40,000) as an acrylic resin, 63parts by weight of 2-methacryloyloxyethyl 2-hydroxypropyl phthalate(Trade name: HO-MPP, by KYOEISHA CHEMICAL Co., LTD.) as aphotopolymerizable monomer, 0.9 part by weight of2,2-dimethoxy-2-phenylacetophenone (Trade name: IR-651, by Ciba Geigy)as a photopolymerization initiator, 0.1 part by weight of an azo dye(Trade name: Dye SS, by Daito Chemix Corporation) as an ultravioletlight absorber, and 100 parts by weight of 3-methoxy-3-methylbutanol asa solvent were mixed and stirred by a stirrer for 3 hours to prepare awater-developable resist composition.

(5.1) Preparation of Photosensitive Glass Paste Composition

20 Parts by weight of the water-developable resist composition (solidcontent: 50%) obtained in (5) and 80 parts by weight of glass frit weremixed and kneaded to prepare a water-developable photosensitive glasspaste composition.

(6) Formation of Spacer Material Layer

The water-developable photosensitive glass paste composition obtained in(5.1) was applied to a support film made of polyethylene terephthalateusing a lip coater, and the resultant layer was dried at 100° C. for 6minutes to completely remove the solvent, thus forming a spacer materiallayer having a thickness of 40 micrometers on the support film. Apolyethylene film having a thickness of 25 micrometers was then stackedon the spacer material layer to produce an unbaked laminate fortransferring the spacer material layer.

(7) Formation of Layers on Glass Substrate

A glass substrate having bus electrodes was preheated to 80° C. On thissubstrate, the unbaked laminate obtained in (4) was then laminated at105° C. with a hot roll laminator while peeling off the removablepolyethylene terephthalate film (Purex A24), to stack the unbakeddielectric layer and burnable intermediate layer on the glass substrate.The air pressure was 3 kg/cm², and the lamination speed was 1.0 m/min.

Subsequently, the removable polyethylene terephthalate film (Purex A53)as the support film was peeled off.

The laminate on the substrate obtained in the aforementioned step waspreheated to 80° C. On the burnable intermediate layer of this laminate,the unbaked laminate obtained in (6) above was laminated at an ordinarytemperature with a roll laminator while peeling off the polyethylenefilm, to stack the spacer material layer on the burnable intermediatelayer. The air pressure was 3 kg/cm², and the lamination speed was 1.0m/min.

(8) Evaluation

The spacer material layer was irradiated with ultraviolet light at anirradiation dose of 300 mJ/cm² from an ultra-high pressure mercury lampthrough a test square pattern mask. Subsequently, the polyethyleneterephthalate as the support film was peeled off, and then the layer wassubjected to spray development using water at a temperature of 30° C. ata jet pressure of 3 kg/cm² for 30 seconds to form a pattern. Adhesionand configuration of the resulting pattern were evaluated using ascanning electron microscope. As a result, the resulting minimum linewidth was 60 micrometers, and no residue of the spacer material layerwas observed between the lines of the pattern, indicating that anexcellent pattern configuration was obtained.

Further, for evaluating the stability of the configuration of thepattern after being baked, the patterned layers produced in accordancewith the above method was subjected to a baking treatment in which thetemperature was elevated at an elevation rate of 1.0° C./min and thenmaintained at 580° C. for 30 minutes. As a result, an excellent bakedpattern was obtained. In addition, the bottom surfaces between the linesof the pattern were flat, and no unevenness due to melting of a residuewas observed.

Example 2

(1) Preparation of Glass Paste Composition

20 Parts by weight of an isobutyl methacrylate/hydroxyethylacrylate=80/20 (wt %) copolymer (Mw: 20,000) as an acrylic resin, 20parts by weight of 3-methoxy-3-methylbutanol as a solvent, and 80 partsby weight of glass frit were mixed and kneaded to prepare a glass pastecomposition

(2) Forming Unbaked Dielectric Layer

The glass paste composition obtained was applied to a support film madeof removable polyethylene terephthalate film (Trade name: Purex A24, byTeijin DuPont Films Japan Limited) using a lip coater, and the resultantlayer was dried at 100° C. for 6 minutes to completely remove thesolvent, thus forming an unbaked dielectric layer having a thickness of60 micrometers on the support film.

(3) Preparation of Composition for Burnable Intermediate Layer

Four parts by weight of polyvinyl alcohol (Trade name: PVA-235, byKuraray Co., Ltd.), and 53 parts by weight of water and 43 parts byweight of isopropyl alcohol as a solvent were mixed and stirred by astirrer for 12 hours to prepare a composition for forming awater-soluble burnable intermediate layer.

(4) Formation of Burnable Intermediate Layer

The obtained composition for forming the burnable intermediate layer wasapplied using a lip coater to the unbaked dielectric layer on thesupport film obtained in (2) above, and the resultant layer was dried at100° C. for 6 minutes to completely remove the solvent, thus forming aburnable intermediate layer having a thickness of 0.5 micrometer.

(5) Preparation of Water-Developable Resist Composition

22 Parts by weight of hydroxypropyl cellulose as a water-solublecellulose derivative, 14 parts by weight of a styrene/hydroxyethylmethacrylate=55/45 (wt %) copolymer (Mw: 40,000) as an acrylic resin, 63parts by weight of 2-methacryloyloxyethyl 2-hydroxypropyl phthalate(Trade name: HO-MPP, by KYOEISHA CHEMICAL Co., LTD.) as aphotopolymerizable monomer, 0.9 part by weight of2,2-dimethoxy-2-phenylacetophenone (Trade name: IR-651, by Ciba Geigy)as a photopolymerization initiator, 0.1 part by weight of an azo dye(Trade name: Dye SS, by Daito Chemix Corporation) as an ultravioletlight absorber, and 100 parts by weight of 3-methoxy-3-methylbutanol asa solvent were mixed and stirred by a stirrer for 3 hours to prepare awater-developable resist composition.

(5.1) Preparation of Photosensitive Glass Paste Composition

20 Parts by weight of the water-developable resist composition (solidcontent: 50%) obtained in (5) and 80 parts by weight of glass frit weremixed and kneaded to prepare a water-developable photosensitive glasspaste composition.

(6) Formation of Spacer Material Layer

The water-developable photosensitive glass paste composition obtained in(5.1) was applied using a lip coater to the burnable intermediate layeron the support film obtained in (4) above, and the resultant layer wasdried at 100° C. for 6 minutes to completely remove the solvent, thusforming a spacer material layer having a thickness of 40 micrometers.Removable polyethylene terephthalate film (Trade name: Purex A53, byTeijin DuPont Films Japan Limited) was then stacked on the spacermaterial layer to produce an unbaked laminate having a five-layerstructure.

(7) Formation of Layers on Glass Substrate

A glass substrate having bus electrodes formed thereon was preheated to80° C. On the substrate, the unbaked laminate obtained in (6) waslaminated at 105° C. with a hot roll laminator while peeling off theremovable polyethylene terephthalate film (Purex A24), to stack theunbaked dielectric layer, burnable intermediate layer, and spacermaterial layer on the glass substrate. The air pressure was 3 kg/cm²,and the lamination speed was 1.0 m/min.

(8) Evaluation

The spacer material layer was irradiated with ultraviolet light at anirradiation dose of 300 mJ/cm² from an ultra-high pressure mercury lampthrough a test square pattern mask. Subsequently, the removablepolyethylene terephthalate film (Purex A53) was peeled off, and then thelayer was subjected to spray development using water at a temperature of30° C. at a jet pressure of 3 kg/cm² for 30 seconds to form a pattern.Adhesion and configuration of the resulting pattern were evaluated usinga scanning electron microscope. As a result, the resulting minimum linewidth was 60 micrometers, and no residue of the spacer material layerwas observed between the lines of the pattern, indicating that anexcellent pattern configuration was obtained.

Further, for evaluating the stability of the configuration of thepattern after being baked, the patterned layer produced in accordancewith the above method was subjected to a baking treatment in which thetemperature was elevated at an elevation rate of 1.0° C./min and thenmaintained at 580° C. for 30 minutes. As a result, an excellent bakedpattern was obtained. In addition, the bottom surfaces between the linesof the pattern were flat, and no unevenness due to melting of a residuewas observed.

Example 3

Four parts by weight of hydroxymethyl cellulose (Trade name: Metolose65S-400, by Shin-Etsu Chemical Co., Ltd.), and 50 parts by weight ofwater and 46 parts by weight of methanol as a solvent were mixed andstirred by a stirrer for 12 hours, to prepare a composition for forminga water-soluble burnable intermediate layer. Except that thiscomposition for the intermediate layer was employed in place of thecomposition for the intermediate layer in Example 1, pattern formationand evaluation thereof were performed in the same way as in Example 1.As a result, the resulting minimum line width was 60 micrometers, and noresidue of the spacer material layer was observed between the lines ofthe pattern, indicating that an excellent pattern configuration wasobtained.

Further, for evaluating the stability of the configuration of thepattern after being baked, the patterned layer produced in accordancewith the above method was subjected to a baking treatment in which thetemperature was elevated at an elevation rate of 1.0° C./min and thenmaintained at 580° C. for 30 minutes. As a result, an excellent bakedpattern was obtained. In addition, the bottom surfaces between the linesof the pattern were flat, and no unevenness due to melting of a residuewas observed.

Example 4

10 parts by weight of a butyral resin (Trade name: S-LEC BX-L, bySekisui Chemical Co., Ltd.) was dissolved in 90 parts by weight ofmethanol, to obtain a solution. This solution was then mixed with 125parts by weight of the composition for the burnable intermediate layerobtained in Example 2 and stirring by a stirrer for 12 hours, to form acomposition for forming a water-swellable burnable intermediate layer.Except that this composition for the intermediate layer was employed inplace of the composition for the intermediate layer in Example 1,pattern formation and evaluation thereof were performed in the same wayas in Example 1. As a result, the resulting minimum line width was 60micrometers, and no residue of the spacer material layer was observedbetween the lines of the pattern, indicating that an excellent patternconfiguration was obtained.

Further, for evaluating the stability of the configuration of thepattern after being baked, the patterned layer produced in accordancewith the above method was subjected to a baking treatment in which thetemperature was elevated at an elevation rate of 1.0° C./min and thenmaintained at 580° C. for 30 minutes. As a result, an excellent bakedpattern was obtained. In addition, the bottom surfaces between the linesof the pattern were flat, and no unevenness due to melting of a residuewas observed.

Comparative Example 1

(1) Preparation of Glass Paste Composition

20 Parts by weight of an isobutyl methacrylate/hydroxyethylacrylate=80/20 (wt %) copolymer (Mw: 20,000) as an acrylic resin, 20parts by weight of 3-methoxy-3-methylbutanol as a solvent, and 80 partsby weight of glass frit were mixed and kneaded to prepare a glass pastecomposition.

(2) Formation of Unbaked Dielectric Layer

The glass paste composition obtained was applied to a support film madeof polyethylene terephthalate using a lip coater, and the resultantlayer was dried at 100° C. for 6 minutes to completely remove thesolvent, thus forming an unbaked dielectric layer having a thickness of60 micrometers on the support film. A polyethylene film having athickness of 25 micrometers was then stacked on the unbaked dielectriclayer to produce an unbaked laminate for transferring the unbakeddielectric layer.

(3) Preparation of Water-Developable Resist Composition

22 Parts by weight of hydroxypropyl cellulose as a water-solublecellulose derivative, 14 parts by weight of a styrene/hydroxyethylmethacrylate=55/45 (wt %) copolymer (Mw: 40,000) as an acrylic resin, 63parts by weight of 2-methacryloyloxyethyl 2-hydroxypropyl phthalate(Trade name: HO-MPP, by KYOEISHA CHEMICAL Co., LTD.) as aphotopolymerizable monomer, 0.9 part by weight of2,2-dimethoxy-2-phenylacetophenone (Trade name: IR-651, by Ciba Geigy)as a photopolymerization initiator, 0.1 part by weight of an azo dye(Trade name: Dye SS, by Daito Chemix Corporation) as an ultravioletlight absorber, and 100 parts by weight of 3-methoxy-3-methylbutanol asa solvent were mixed and stirred by a stirrer for 3 hours to prepare awater-developable resist composition.

(3.1) Preparation of Photosensitive Glass Paste Composition

20 Parts by weight of the water-developable resist composition (solidcontent: 50%) obtained in (3) and 80 parts by weight of glass frit weremixed and kneaded to prepare a water-developable photosensitive glasspaste composition.

(4) Formation of Spacer Material Layer

The water-developable photosensitive glass paste composition obtained in(3.1) was applied to a support film made of polyethylene terephthalateusing a lip coater, and the resultant layer was dried at 100° C. for 6minutes to completely remove the solvent, thus forming a spacer materiallayer having a thickness of 40 micrometers on the support film. Apolyethylene film having a thickness of 25 micrometers was then stackedon the spacer material layer to produce an unbaked laminate fortransferring the spacer material layer.

(5) Formation of Layers on Glass Substrate

A glass substrate having bus electrodes formed thereon was preheated to80° C. On the substrate, the unbaked laminate obtained in (2) waslaminated at 105° C. by a hot roll laminator while peeling off thepolyethylene film, to stack the unbaked dielectric layer on the glasssubstrate. The air pressure was 3 kg/cm², and the lamination speed was1.0 m/min. Subsequently, the polyethylene terephthalate film as thesupport film was peeled off.

The unbaked dielectric layer obtained in (5) above was then preheated to80° C. On the surface of the unbaked dielectric layer, the unbakedlaminate obtained in (4) was laminated at an ordinary temperature with aroll laminator while peeling off the polyethylene film, to stack thespacer material layer on the unbaked dielectric layer. The air pressurewas 3 kg/cm², and the lamination speed was 1.0 m/min.

(6) Evaluation

The spacer material layer was irradiated with an ultraviolet light at anirradiation dose of 300 mJ/cm² from an ultra-high pressure mercury lampthrough a test square pattern mask. Subsequently, the polyethyleneterephthalate as the support film was peeled off, and then the layer wassubjected to spray development using water at a temperature of 30° C. ata jet pressure of 3 kg/cm² for 30 seconds to form a pattern. Adhesionand configuration of the resulting pattern were evaluated using ascanning electron microscope. As a result, the resulting minimum linewidth was 60 micrometers and an excellent pattern form was obtained.However, a slight residue of the spacer material layer was observedbetween the lines of the pattern.

Further, for evaluating the stability of the configuration of thepattern after being baked, the patterned layer produced in accordancewith the above method was subjected to a baking treatment in which thetemperature was elevated at an elevation rate of 1.0° C./min and thenmaintained at 580° C. for 30 minutes. As a result, the bottom surfacesbetween the lines of the pattern were not flat.

As explained above, with the present invention, an intermediate layer,which is water-soluble or water-swellable and which is capable ofcompletely burning up in a burning treatment, may be formed between theunbaked dielectric layer and the unexposed, photosensitive unbakedspacer material layer, and the burnable intermediate layer may bedissolved in or swollen with water upon washing the pattern with waterafter or simultaneously with the development of the exposed spacermaterial layer. Therefore, the spacer layer remaining in the region thathas been subjected to the removing development can be easily removed, sothat the thickness of the region subjected to the removing developmentbecomes uniform, thus making it possible to produce a front plate of aplasma display device having uniform discharge properties and lighttransmittance.

REFERENCES

-   1. Japanese Patent Application Laid-open No. 2002-150949-   2. Japanese Patent Application Laid-open No. 2002-328467

1. An unbaked laminate for producing a front plate of a plasma displaydevice having a glass substrate having a surface on which electrodes areformed, a dielectric layer formed on said surface, and spacer layersformed on said dielectric layer, said laminate consisting of: aremovable support film; a photosensitive unbaked spacer material layerformed on said removable support film; and a burnable intermediate layerformed on said spacer material layer, said intermediate layer beingwater-soluble or water-swellable.
 2. The unbaked laminate according toclaim 1, wherein said spacer material layer consists of a photosensitiveglass paste material which is capable of being developed by the use ofwater.
 3. The unbaked laminate according to claim 1, wherein saidburnable intermediate layer comprises a resin selected from the groupconsisting of a polyvinyl alcohol, a polyvinyl alcohol derivative, awater-soluble cellulose, and mixtures thereof.
 4. The unbaked laminateaccording to claim 1, wherein said burnable intermediate layer has athickness of 5 micrometers or less.
 5. An unbaked laminate for producinga front plate of a plasma display device having a glass substrate havinga surface on which electrodes are formed, a dielectric layer formed onsaid surface, and spacer layers formed on said dielectric layer, saidlaminate comprising: a removable support film; a photosensitive unbakedspacer material layer formed on said removable support film; a burnableintermediate layer formed on said spacer material layer, saidintermediate layer being water-soluble or water-swellable; and anon-photosensitive unbaked dielectric layer formed on said burnableintermediate layer, said dielectric layer consisting of a glass pastematerial.
 6. the unbaked laminate according to claim 5, wherein saidspacer material layer consists of photosensitive glass paste materialwhich is capable of being developed by the use of water.
 7. The unbakedlaminate according to claim 5, further comprising a removable protectionfilm covering a surface of said laminate, said surface being on theother side of said removable support film.
 8. The unbaked laminateaccording to claim 5, wherein said burnable intermediate layer comprisesa resin selected from the group consisting of a polyvinyl alcohol, apolyvinyl alcohol derivative, a water-soluble cellulose, and mixturethereof.
 9. The unbaked laminate according to claim 5, wherein saidburnable intermediate layer has a thickness of 5 micrometers or less.10. A method for producing a front plate of a plasma display devicehaving a glass substrate having a surface on which electrodes areformed, a dielectric layer formed on said surface, and spacer layersformed on said dielectric layer, said method comprising the steps of:(a) forming on said surface of the substrate a non-photosensitiveunbaked dielectric layer consisting of a glass paste material, aburnable intermediate layer which is water-soluble or water-swellable,and a photosensitive unbaked spacer material layer in this order; (b)irradiating said spacer material layer with a patterning light, anddeveloping said spacer material layer, to constitute a patterned spacermaterial layer; (c) baking said non-photosensitive unbaked dielectriclayer, said burnable intermediate layer, and said patterned spacermaterial layer simultaneously, to burn up said burnable intermediatelayer and forming said dielectric layer and said spacer layers on saidglass substrate simultaneously.
 11. The method for producing the frontplate of the plasma display device according to claim 10, wherein saidstep (a) comprises: forming on a removable support film a burnableintermediate layer which is water-soluble or water-swellable, and saidunbaked dielectric layer consisting of a glass paste material in thisorder to prepare a laminate; attaching said laminate on said glasssubstrate so that said unbaked dielectric layer faces said surface ofsaid glass substrate, said surface having said electrodes; removing saidremovable support film from said burnable intermediate layer, to uncoversaid burnable intermediate layer; and forming a photosensitive unbakedspacer material layer on said burnable intermediate layer.
 12. Themethod for producing the front plate of the plasma display deviceaccording to claim 10, wherein said step (a) comprises: forming on aremovable support film a photosensitive unbaked spacer material layer,and a burnable intermediate layer which is water-soluble orwater-swellable in this order to prepare a laminate; forming saidnon-photosensitive unbaked dielectric layer consisting of a glass pastematerial on the surface of said glass substrate, said surface havingsaid electrodes; and attaching said laminate on said unbaked dielectriclayer so that said burnable intermediate layer faces said unbakeddielectric layer.
 13. The method for producing the front plate of theplasma display device according to claim 10, wherein said step (a)comprises: forming on a removable support film a photosensitive unbakedspacer material layer, a burnable intermediate layer which iswater-soluble or water-swellable, and said unbaked dielectric layerconsisting of a glass paste material in this order to prepare alaminate; and attaching said laminate on said glass substrate so thatsaid unburned dielectric layer faces the surface of said glasssubstrate, said surface having said electrodes.
 14. An unbaked laminatefor producing a front plate of a plasma display device having a glasssubstrate having a surface on which electrodes are formed, a dielectriclayer formed on said surface, and spacer layers formed on saiddielectric layer, said laminate consisting of: a removable support film;a photosensitive unbaked spacer material layer formed on said removablesupport film; a burnable intermediate layer formed on said spacermaterial layer, said intermediate layer being water-soluble orwater-swellable; and a removable protection film covering a surface ofsaid laminate, said surface being on the other side of said removablesupport film.